User Terminal, Radio Base Station, and Radio Communication Method

1. A terminal comprising: a processor that configures, based on higher layer signaling, a plurality of candidate resources, each corresponding to one of a first mapping that maps a given number of sounding reference signals in one resource block in a frequency direction, and a second mapping that maps a number of the sounding reference signals that is less than the given number of the sounding reference signals in the one resource block in the frequency direction; and a transmitter that transmits the sounding reference signals based on the candidate resources, wherein information on an identifier used in a generation of a sequence of the sounding reference signals is notified by higher layer signaling from a base station, and wherein the processor determines, based on information about resource allocation of the sounding reference signals, whether to transmit the sounding reference signals using different subcarriers in a plurality of symbols or to transmit the sounding reference signals using same subcarriers in a plurality of symbols.

2. The terminal according to claim 1 , wherein the processor selects a resource for transmission of the sounding reference signals based on information included in a downlink control signal.

3. A base station comprising: a processor that transmits to higher layer signaling to configure a plurality of candidate resources, each corresponding to one of a first mapping that maps a given number of sounding reference signals in one resource block in a frequency direction, and a second mapping that maps a number of the sounding reference signals that is less than the given number of the sounding reference signals in the one resource block in the frequency direction for a terminal; and a receiver that receives the sounding reference signals transmitted based on the candidate resources configured by the terminal, wherein information on an identifier used in a generation of a sequence of the sounding reference signals is notified by higher layer signaling to the terminal, and wherein the terminal determines, based on information about resource allocation of the sounding reference signals, whether to transmit the sounding reference signals using different subcarriers in a plurality of symbols or to transmit the sounding reference signals using same subcarriers in a plurality of symbols.

4. A radio communication method for a terminal comprising: configuring, based on higher layer signaling, a plurality of candidate resources, each corresponding to one of a first mapping that maps a given number of sounding reference signals in one resource block in a frequency direction, and a second mapping that maps a number of the sounding reference signals that is less than the given number of the sounding reference signals in the one resource block in the frequency direction; and transmitting the sounding reference signals based on the candidate resources, wherein information on an identifier used in a generation of a sequence of the sounding reference signals is notified by higher layer signaling from a base station, and wherein the terminal determines, based on information about resource allocation of the sounding reference signals, whether to transmit the sounding reference signals using different subcarriers in a plurality of symbols or to transmit the sounding reference signals using same subcarriers in a plurality of symbols.

5. A system comprising a terminal and a base station, wherein: the base station comprises: a processor of the base station that transmits to higher layer signaling to configure a plurality of candidate resource, each corresponds to one of a first mapping that maps a given number of sounding reference signals in one resource block in a frequency direction, and a second mapping that maps a number of the sounding reference signals that is less than the given number of the sounding reference signals in the one resource block in the frequency direction for the terminal; and a receiver that receives the sounding reference signals transmitted based on the candidate resources configured by the terminal, the terminal comprises: a processor of the terminal that configures, based on the higher layer signaling, the candidate resources; and a transmitter that transmits the sounding reference signals based on the candidate resources, wherein information on an identifier used in a generation of a sequence of the sounding reference signals is notified by higher layer signaling from the base station to the terminal, and wherein the processor of the terminal determines, based on information about resource allocation of the sounding reference signals, whether to transmit the sounding reference signals using different subcarriers in a plurality of symbols or to transmit the sounding reference signals using same subcarriers in a plurality of symbols.